The present invention relates to a roof ventilator for exhausting air from and taking air into a room. More particularly, the present invention relates to a roof ventilator adapted for use in locations where a desired temperature must be constantly maintained, such as for example, a laboratory or an agricultural warehouse.
In the locations mentioned above, the maintenance of a constant temperature is required because otherwise, detrimental effects will be produced. In conventional ventilating systems, problems have been encountered in either admitting unexpected cold or warm outside air into rooms, or in allowing the inside air to escape therefrom. In order to overcome these problems, a number of proposals have been made, including a ventilator having a floating shutter which operates against the opening in the piping. According to this device, when the ventilator is in operation, the shutter rises up due to air pressure produced by a power driven fan, thereby creating a gap between the hood and the opening in the pipe. When the operation of the ventilator is stopped, the shutter moves downwards due to gravity to ensure the closure of the pipe. However, it has been proven that the upward movement of the shutter is prevented by the pneumatic repercussion under the hood, and also by the intake or exhaust air whirling thereunder which produces an unstable movement of the shutter. In addition, the shutter is subjected to vibrations, which causes disagreeable noises. Furthermore, the raising of the shutter, even if successfully achieved, is possible only when air is exhausted from the building through the pipe.
An object of the present invention is to avoid the prior art disadvantages found in roof ventilators used for introducing air into and removing air from a specific location.
Another object of the present invention is to provide a roof ventilator containing a shutter which is capable of preventing air from passing therethrough when the ventilator is not in operation, thereby maintaining a desired constant room temperature.
Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter; it should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
Pursuant to the present invention, a floating shutter is carried by foldable supporters which fold in the upward direction due to the centrifugal action produced when a ventilating fan is driven in either direction for taking in or exhausting air through the device. The movement of the shutter is facilitated by a gearing arrangement associated with the foldable supporters. Accordingly, when the shutter is forced in the upward direction, or lowered as a result of gravity, the movement of the shutter is ensured without producing any substantial noise and with little chance of failure.